Ultrasound-assisted extraction of proteins from malt bagasse: process intensification and functionality evaluation

Abstract

The increasing demand for new sources of plant-based proteins has become a sustainability issue associated with healthier nutritional habits. Their functional properties also play an important role in the technological aspects of food formulation. Malt bagasse, for example, is shown to be a sustainable and renewable byproduct of the brewing industry with outstanding protein contents. However, the suitable use of the protein fraction depends on efficient extraction processes. For this, high-intensity ultrasound (US) has appeared as an emerging technology to assist the extraction process due to the effects caused in the solid-liquid interface of materials. On the other hand, the use of alkaline hydrogen peroxide (APH) has been shown to be an efficient oxidant with low environmental impact to pretreat biomass and increase its accessibility. Given the advantages of both methods, the general objective of this proposal will be focused on evaluating the extraction efficiency and functionality of malt bagasse proteins with APH and US. The chemically characterized malt bagasse will be put in contact with solutions of different concentrations of APH and different nominal potentials of US. As responses, it will be analyzed: the extraction yield, the hygroscopicity and coloration of the protein extract, the water and oil retention capacity of the raffinate and the protein extract, in addition to its foaming and emulsifying capacities. In this way, it is expected to obtain a process with adequate conditions that intensify the conventional extraction of proteins from malt bagasse and that preserve its functional properties for future applications in food.